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Orycteropodidae

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Orycteropodidae
Temporal range: 20–0 Ma Early Miocene to Recent[1]
Orycteropus afer - Aardvark
Scientific classification
Kingdom:
Phylum:
Class:
Superorder:
(unranked):
Order:
Tubulidentata

Huxley, 1872
Family:
Orycteropodidae

Gray, 1821
Genera

Orycteropus
Amphiorycteropus
Leptorycteropus
Myorycteropus[1]

Orycteropodidae is a family of afrotherian mammals. Although there are many fossil species, the only species surviving today is the aardvark, Orycteropus afer. Orycteropodidae is recognized as the only family within the order Tubulidentata, so the two are effectively synonyms.[1][2]

Only recently did scientists discover that the aardvark and the anteater evolved from two different families and separated the two species. They were classified in the order Edentata due to their similar physical characteristics and diets. The phylogeny of this family has never been fully analyzed, making it hard to trace back the evolutionary history, and the amount of unknown information limits the knowledge of the species.

Orycteropodidae members are polygynous, the females providing care for the young. They are territorial, and only cross paths to breed. The males' genitals create a musk while females create this musk from glands in their elbows, this scent helps mating occur. The gestation period lasts about 7 months, and they are dependent upon the mother until they are 6 months of age, becoming sexually mature at 2 years of age. Breeding occurs once a year, they produce one offspring, and will have maybe one to two more in their lifetime.

Representatives of the order Tubulidentata have been located from the Oligocene in what is now Europe, and it is believed that the order probably originated around 65–70 million years ago or in the Paleocene.[3][4] They are thought to be closely related to the now extinct Ptolemaiida, a lineage of carnivorous afrotheres.[5][6] The family arose in Africa in the Early Miocene Epoch, and spread to Eurasia later in the Miocene. Most of the family's diversity had become extinct by the end of the Pliocene.[1]

Aardvarks are myrmecophagous, feeding almost exclusively on termites and ants. They rely on their sense of smell to find most of their food and hunt at night.

Characteristics

Orycteropodidae skeleton

A few anatomical characters unite the Orycteropodidae and Tubulidentata.

  • the occipital region has extensive mastoid exposure
  • the teeth have a distinctive structure called tubulidentate microstructure. These animals lack incisors and canines, and have between 20-22 teeth. These teeth also lack enamel, and are just rounded structures of dentine. The teeth are evergrowing, unrooted, and diphyodont. Another unique trait is that their small milk teeth are lost before the animal is born.
  • the femur has a pectineal tubercle
  • the diaphysis of the tibia is curved mediolaterally


Classification

This classification follows Lehmann 2009.[1][7]

  • Genus †Scotaeops Ameghino 1887 [Scoteops (sic) Ameghino 1894]
  • Genus †Archaeorycteropus Ameghino 1905
  • Genus †Palaeorycteropus Filhol 1893 [Palaeoryctoropus (sic) Filhol 1893]
  • Genus † Myorycteropus MacInnes, 1956
    • M. africanus MacInnes, 1956 [Orycteropus africanus MacInnes 1955] type species
    • aff. M. chemeldoi (Pickford, 1975) [Orycteropus chemeldoi Pickford 1975]
    • aff. M. minutus (Pickford, 1975) [Orycteropus minutus Pickford 1975]
  • Genus †Leptorycteropus Patterson, 1975
  • Genus †Amphiorycteropus Lehmann 2009
    • A. gaudryi (Major, 1888) [Orycteropus gaudryi Major 1888] type species
    • A. abundulafus (Lehmann et al., 2005) [Orycteropus abundulafus Lehmann et al. 2005][8]
    • A. browni (Colbert, 1933) [Orycteropus browni Colbert 1933; Orycteropus pilgrimi Colbert 1933]
    • A. depereti (Helbing, 1933) [Orycteropus depereti Helbing 1933]
    • A. mauritanicus (Arambourg, 1959) [Orycteropus mauritanicus Arambourg 1959]
    • aff. A. pottieri (Ozansoy, 1965) [Orycteropus pottieri Ozansoy 1965]
    • aff. A. seni (Tekkaya, 1993) [Orycteropus seni Tekkaya 1993]
  • Genus Orycteropus Geoffroy St. Hilaire 1796 [Oryctopus (sic) Rafinesque 1815; Oryctheropus (sic) Muirhead 1819; Orajeteropus (sic) Hill 1913]
    • O. crassidens MacInnes, 1956
    • O. djourabensis Lehmann et al. 2004
    • O. afer (Pallas 1776) Aardvark (type species)
      • O. a. capensis (Gmelin 1788) [Myrmecophaga capensis Gmelin 1788; Orycteropus capensis (Gmelin 1788)] (Cape Aardvark)
      • O. a. senegalensis Lesson 1840 [Orycteropus senegalensis Schinz 1845] (Western/Senegambian Aardvark)
      • O. a. haussanus Matschie 1900 [Orycteropus haussanus Matschie 1900] (Hausa Aardvark)
      • O. a. adametzi Grote 1921 [Orycteropus adametzi]
      • O. a. leptodon Hirst 1906 [Orycteropus leptodon Hirst 1906] (Cameroon Aardvark)
      • O. a. erikssoni Lönnberg 1906 [Orycteropus erikssoni Lonnberg 1906; Orycteropus erikssoni erikssoni] (Eriksson's/North Congo Aardvark)
      • O. a. albicaudus Rothschild 1907 (South-western/Damara Aardvark)
      • O. a. angolensis Zukowsky & Haltenorth 1957 [Orycteropus angolensis] (Angolan Aardvark)
      • O. a. afer (Pallas 1776) [Orycteropus afer wertheri Matschie 1898; Orycteropus wertheri Matschie 1900 (East African/Bagamoyo Aardvark)] (Southern Aardvark)
      • O. a. wardi Lydekker 1908 [Orycteropus wardi] (Congo/Ward's Aardvark)
      • O. a. observandus Grote 1921 [Orycteropus observandus]
      • O. a. matschiei Grote 1921 [Orycteropus matschiei]
      • O. a. lademanni Grote 1911 [Orycteropus lademanni]
      • O. a. ruvanensis Grote 1921 [Orycteropus ruvanensis] (Ruwana Aardvark)
      • O. a. faradjius Hatt 1932 [Orycteropus erikssoni faradjius] (Faradje Aardvark)
      • O. a. kordofanicus Rothschild 1927 [Orycteropus kordofanicus] (Kordofan Aardvark)
      • O. a. aethiopicus Sundevall 1843 [Orycteropus aethiopicus] (Northeastern/Abyssinian Aardvark)
      • O. a. somalicus Lydekker 1908 [Orycteropus somalicus] (Somalia Aardvark)

Footnotes

  1. ^ a b c d e Lehmann 2009
  2. ^ Schlitter 2005, p. 86
  3. ^ Shoshani 2002, p. 619
  4. ^ Shoshani 2002, p. 620
  5. ^ Cote S, Werdelin L, Seiffert ER, Barry JC (March 2007). "Additional material of the enigmatic Early Miocene mammal Kelba and its relationship to the order Ptolemaiida". Proc Natl Acad Sci USA. 104 (13): 5510–5. Bibcode:2007PNAS..104.5510C. doi:10.1073/pnas.0700441104. PMC 1838468. PMID 17372202.
  6. ^ Seiffert, Erik R (2007). "A new estimate of afrotherian phylogeny based on simultaneous analysis of genomic, morphological, and fossil evidence". BMC Evolutionary Biology. 7 (1): 224. doi:10.1186/1471-2148-7-224. PMC 2248600. PMID 17999766.{{cite journal}}: CS1 maint: unflagged free DOI (link)
  7. ^ Mikko's Phylogeny Archive [1] Haaramo, Mikko (2007). "Tubulidentata – aardwarks". Retrieved 30 December 2015.
  8. ^ Lehmann et al. 2005

References

Further reading

  • "A sub-complete fossil aardvark (Mammalia, Tubulidentata) from the Upper Miocene of Chad". doi:10.1016/j.crpv.2005.12.016
  • MacInnes D. G. (1956). Fossil Tubulidentata from East Africa. British Museum (Natural History), London. Fossil mammals of Africa series; no. 10. 46 pp.